A French study has found nitrogen dioxide (NO2 ) appears to elevate the risk of needing cataract surgery, especially among people living in urban areas.
The same study also found that black carbon (BC) may increase the risk of neovascular age-related macular degeneration (nAMD).
The authors said the study “provides new insights into the impact of air pollution on ocular ageing… highlighting the distinct effects observed between urban and rural populations”.
The investigators examined the influence of air pollution exposure on the incidence of cataract surgery and nAMD in two groups in France: The Gazel cohort (more than 17,000 employees of a French energy company) and the Constances cohort (just over 18,000 people recruited from social security affiliates). The investigators selected individuals who were aged at least 53 years and had them complete questionnaires and health assessments over a 10-year period.
Using data from the French National Health System, the investigators identified 5,543 incident cataract surgery cases and 266 nAMD cases among the overall group. Just under three quarters of participants lived in urban areas, and two-thirds had never smoked.
The findings suggest that exposure to higher levels of NO2 is associated with an increased risk of cataract surgery.
According to the researchers, urban dwellers were exposed to more than 34.8 μg/m3 of NO2 and experienced an 8% greater risk of cataract surgery (95% confidence interval [CI], 1.01-1.16, P =.017).
Among the Constances cohort, but not in the general population or the Gazel cohort, people who possessed the highest quartile of black carbon exposure (at least 2.33 10−5/m) experienced an 88% higher risk of nAMD (95% CI, 1.03-3.45, P =.041) compared with individuals with the lowest quartile.
The investigators did not find a link between pollutants and the Gazel cohort or rural participants in the Constances cohort. Incident cataract surgery was not tied to NO2 exposure among rural participants, and it was not linked with particle matter or BC exposure.
“We observed that the impact of pollution was significant only among urban residents for cataract surgery, suggesting an interaction with urban versus rural settings.
“The differences in results between urban and rural areas may be explained by variations in pollution levels, as well as differences in pollution sources, with potentially lower exposure to traffic-related emissions in rural regions.”
The authors said the limited number of cases may have affected the statistical power of the study regarding nAMD. “Overall, our results support a potential role of air pollution in ocular ageing; however, further studies are needed to better characterise this relationship and to clarify the underlying mechanisms involved,” they wrote.
References available at mivision.com.au.